1. Field of the Invention
The present invention relates to bulkheads for vehicle bodies containing refrigeration systems in general. More specifically to refrigeration unit protecting and air flow duct bulkheads that collapse to reduce the overall depth.
2. Description of Prior Art
Previously, bulkheads have been used in conjunction with refrigerated trucks and trailers. Although these bulkheads are of similar construction, there are two basic uses. The first is to isolate the interior into compartments to provide different environmental conditions of temperature and humidity or to reduce the volume being refrigerated. The second purpose of a bulkhead is to protect a mechanical vapor cycle refrigeration unit from physical damage during loading and load shifting while operating over the road. Further, the bulkhead provides an air passageway for the cooled air to enter the return side of the evaporator coil when a load is touching the interior front wall. This invention is related to the latter utility with prior art limited to fixed bulkheads constructed integral with the trailer wall. These are usually fabricated of a wood or metal structure attached vertically and plywood or composition material affixed to the exposed surface forming a protective shield with vertical openings in between. The plywood is located a distance up from the floor, providing an opening for the return air. Other art utilizes a series of rails usually of structural metal located strategically on the front wall to accomplish the same purpose, except the plywood is omitted.
Learmont in U.S. Pat. No. 3,057,284 teaches a movable bulkhead for the former purpose hinging from the top to compartmentize the trailer with a propeller fan moving air from one compartment to the other. The bulkhead also moves forward and aft on rollers with tracks embedded longitudinally into the trailer walls. The apparatus also hinges from the top and swings upward to the ceiling for storage. This top hinging may become dangerous when worn or improperly latched and the thickness of the bulkhead remains the same regardless of its position. U.S. Pat. No. 2,633,714 issued to Wehby discloses interior doors that open at the center and swing planar to the walls, however, the volume of the door is not reduced but is only relocated to the interior sides of the trailer.
Other patents which lend themselves to refrigerated trailer bulkheads and may be considered material in the sense of prior art with respect to this application are U.S. Pat. Nos. 1,704,758 of Meinhardt, and 2,895,309 issued to Kuhlmeier. However, neither of these are considered to have teachings which disclose or suggest the overall arrangement of this invention.